1. Field of the Invention
The present invention relates generally to a damper and its method of fabrication, and more particularly, to a damper having a locally coated material fabricated by a printing technique.
2. The Prior Arts
Typical component parts of a loudspeaker include a diaphragm, a voice coil, and a damper placed between the diaphragm and the voice coil. The damper can keep the voice coil at a correct position in the magnetic gap, ensure that the vibrating system reciprocates axially upon the application of a force on the voice coil, cooperate with the voice coil and the diaphragm to determine the resonance efficiency of the loudspeaker, and prevent dust in the magnetic gap.
For fabricating the damper, a roll of a fiber fabric is usually soaked in a resin bath, baked, cut and severed to form an entire damper. The fiber fabric after being baked has an increased stiffness owing to the prior resin bath. Unfortunately, the damper fabricated according to the aforementioned method may have an excessive stiffness and lack flexibility, which may create noise and affect the reproduction of bass sound.
Taiwan Patent No. M396605 and Taiwan Patent Application Publication No. 201129125 describe dampers and its manufacture method. According to these prior disclosures, a coating material is applied on a predetermined coating region of the damper, whereby the region of the formed damper having the coating material can be softened compared to other regions having no coating material. This can address the excessive stiffness problem in the fabrication of the damper.
In the aforementioned prior art method, the fiber fabric is extended in the warp direction, and the ability of the fiber fabric to extend and elastically retract is usually better in the weft direction than in the warp direction. As a result, the predetermined coating region can have more inward wrinkles in the weft direction than in the warp direction, resulting in an irregular distribution of the coating material on the surface of the damper. For example, the predetermined coating region may initially have a circular shape, which may become an oval shape after baking of the fiber fabric applied with the coating material. The region of the damper softened by the coating material thus may become significantly irregular and greatly differ from the initial circular shape, which may subject to even more noise and adversely affect the sound quality of the loudspeaker.
Moreover, the inward wrinkles formed on the predetermined coating region of the fiber fabric in the weft direction may differ among different dampers, so that the softened region may be inconsistent between different dampers. As a result, the resonance efficiency of each loudspeaker determined by the damper, the voice coil and the diaphragm may not be similar. In other words, the sound quality of the manufactured loudspeakers may be inconsistent owing to the aforementioned problem.